Miniaturization of mechanical devices such as gears, bearings, and even motors has been achieved up to now through silicon micromechanics. However, these devices still have limited lifetimes and their dimensions are in the tens of microns range. Several biological systems use rotary motion, such as flagellar motors (appr. 50 nm in size) and molecular motors (appr. 10 nm in size) based on H.sup.+ adenosine triphosphate synthase. Molecular-based mechanical devices have also been proposed.